This invention relates, generally, to the field of telecommunications/mobile terminals and, more particularly, it relates to the development of an architecture which allows mobile (wireless) terminals and the like to communicate and coexist independent of the protocol version.
Increasingly, companies, corporations, organizations or associations and the like and even individuals are finding more and more that wireless communication is becoming an indispensable addition to the more traditional wired versions to satisfy the needs for mobility, relocation, ad hoc networking, and coverage of locations difficult to wire. Recently, a new technology has been developing which can expand the use of mobile (portable) phones and related hand-held mobile terminals using the same ISM (industrial, scientific and medical) band as that employed by the wireless LAN (local area network) communication which conforms to the IEEE 802.11 standard. This new technology is known as the Bluetooth wireless technology which is a low-powered radio technology which allows users to make effortlessly, wireless and instant connections between various communication devices, such as mobile (wireless) phones and desktop and notebook computers and the like. A communication linkup operating under the Bluetooth system, such as based on the standard dated Nov. 29, 1999, operates on the unlicensed (free) 2.4 GHz ISM frequency band. In the vast majority of countries (including USA, Europe and most other countries) this frequency band actually is 2400-2483.5 MHz. The Bluetooth special interest group (SIG), which is a consortium of leading companies in the related industries, has launched a campaign to achieve total harmonization of the frequency band.
The sophisticated mode of transmission adopted in the Bluetooth specification ensures protection from interference and security of data. A frequency hop transceiver is applied to combat interference and fading. A shaped, binary FM modulation is applied to minimize transceiver complexity. The symbol rate is 1 Ms/s. A slotted channel is applied with a nominal slot length of 625 xcexcs. For full duplex transmission, the time-division duplex (TDD) scheme is employed. With regard to channel linkup, information is exchanged through packets. Each packet is transmitted on a different hop frequency.
The Bluetooth protocol uses a combination of circuit and packet switching. Slots can be reserved for synchronous packets (e.g., voice traffic). Bluetooth can support an asynchronous data channel, up to three simultaneous synchronous voice channels or a channel which simultaneously supports asynchronous data as well as synchronous voice. Asynchronous data traffic corresponds to an ACL (asychronous connection-less) link while sychronous traffic is associated with voice traffic and is supported by an SCO (synchronous connection-oriented) link.
The Bluetooth specification has two power levels defined, namely, a lower power level that generally covers the small surroundings such as within a room, and a higher power level that can cover a medium range, such as within a home. That is, conventionally, software controls and identity coding built into each microchip ensure that only those units preset by their owners can communicate.
Wireless devices which conform to Bluetooth technology are supported by a Bluetooth system, such as 10 shown in FIG. 1 of the drawings, consisting of a radio unit 11, a link control unit 12, and a support unit for link management and host terminal interface functions 13. The link controller (LC) in the Bluetooth system (also referred to as the baseband section) describes the specifications of the digital signal processing portion of the hardware, that is, the Bluetooth link controller carries out the baseband protocols and other low-level link routines. As to the link manager (LM), it is a software entity which carriers out link setup, authentication, link configuration and other protocols. The link manager discovers other remote LMs and communicates with them via the link manager protocol (LMP). Details regarding the servicing by a link controller and link manager have been standardized by the Bluetooth SIG.
Software interoperability begins with the Bluetooth link level protocol responsible to the protocol multiplexing, device and service discovery and segmentation and reassembly. Bluetooth devices must be able to recognize each other and load the appropriate software to discover the high level abilities each device supports. This is all supported by Bluetooth software framework. Interoperability at the application requires identical protocol stacks. Different classes of Bluetooth devices including (although not limited thereto) PCs, hand-helds, PDAs (personal digital assistants), headsets, mobile/cellular phones have different compliance requirements. For example, you would not expect a Bluetooth headset to contain an address book. Headsets compliance implies Bluetooth radio compliance, audio capability, and device discovery protocols. More functionality would be expected from cellular phones, hand-held or notebook computers. In order to achieve this interoperability, the Bluetooth software framework employs a complete protocol stack which comprises both Bluetooth specification protocols like LMP and L2CAP (logical link control and adaptation protocol) and non-Bluetooth-specific protocols like OBEX (object exchange protocol) and UDP (user datagram protocol), etc. In designing the protocols and the whole protocol stack, according to the present Bluetooth standard, the main principle has been to maximize the re-use of existing protocols for different purposes at the higher level, instead of xe2x80x9cre-inventing the wheelxe2x80x9d once again. Thus, the open specification afforded by the Bluetooth protocol stack permits the development of a large number of new applications that take full advantage of the capabilities of the Bluetooth technology.
The Bluetooth system provides a point-to-point wireless connection, in which two Bluetooth units are involved. FIG. 2A of the drawings illustrates a point-to-point linkup involving wireless device BTM, which has taken the role of the master, and wireless device BTS, which is the slave in this connection. Other types of connections, which may be referred to as WPANs (wireless personal area networks) can also be effected under the support of a Bluetooth system. For example, FIG. 2B shows a point-to-multipoint connection 21 in which the channel is shared among several Bluetooth units. In this example, wireless device BTM represents the master unit and devices BTS1-BTS7 represent the slave units, which are linked to the channel access code set by the master device.
In an ad hoc or WPAN linkup scheme such as shown in FIG. 2B, in which two or more units share the same channel, the ad hoc network is referred to as a piconet. A piconet may begin with two connected devices, such as a portable PC (Personal Computer) and a cellular phone, and may grow to eight connected devices, which device may also be identical. However, once a piconet is formed, one unit will act as a master and the remainder as the slaves for the duration of the piconet connection. It should be noted, at present, a piconet is limited to seven slaves. However, many more slaves are able to remain locked to the master of the piconet in a so-called parked state. These parked slaves cannot be active on the channel but may remain synchronized to the master. Both for active and parked slaves, the channel access is controlled by the master.
Multiple piconets with overlapping coverage areas form a scatternet. In this situation, each piconet can only have a single master. However, slaves are able to participate in different piconets on a time-division multiplex basis. In addition, a master in one piconet can be a slave in another piconet. The piconets shall not be time- or frequency-synchronized. Each piconet has its own hopping channel. FIG. 2C of the drawings is an example of a scatternet 22 involving overlapping coverage areas of a number of piconets. In this example of scatternet, 23, 24 and 25 are separate piconets which have one or more devices as components of more than one piconet. It is noted that device BTS/BTM acts as a slave in piconet 23 and as the master of the point-to-point linkup 24.
Wireless devices such as mobile/cell phones, as one example of a wireless device, will no longer have to be limited to, for example, a basic service set in a base station sub-system (BSS) link, which typically consists of a number of stations executing the same Medium Access Control (MAC) protocol in competing for access to the same shared medium. In a wireless local area network (WLAN) linkup, a single access transceiver can support a small group of co-located users within a range of less than one hundred to several hundred feet, typically. On the other hand, Bluetooth technology will enable users to connect their mobile computers, digital mobile/cell phones, handheld devices, network access points and other mobile devices by wireless short-range radio links, unimpeded by line-of-sight restrictions using substantially less power. Bluetooth technology will increase the ease of wireless communication by the ordinary citizen, as well as the scope of wireless connectivity. Also, since Bluetooth is limited to short range communication, typically, under 10 meters, for example, 2-3 meters, it requires a very little power level. As stated earlier, however, the range may be extended to a 100 meters or more through simply increasing the transmit power level. Simply put, this Bluetooth technology enables portable electronic devices to connect and communicate wirelessly by a short range, ad hoc networks.
In order to function on a worldwide basis, Bluetooth requires a radio frequency that is license-free and open to any radio. When the Bluetooth radio is applied to a mobile phone, the user can leave the mobile phone clipped to his belt or in a pocket and walk around for the entire dial-up-connection. Also, because there are no line-of-sight requirements for Bluetooth devices, it is well suited for wireless connectivity, such as between a mobile phone and a notebook computer or between two mobile phones. For example, with Bluetooth, a person could synchronize one""s phone with a PC without taking the phone out of one""s pocket or briefcase. The users would automatically receive E-mail on their notebook or laptop computers by the digital cellular phones in their pockets or synchronize their primary PC with their hand-held computer without taking it out of their briefcase.
The omni-directional capability of Bluetooth allows synchronization to start when the phone is brought into the range of the PC. It allows for a gross data rate of one megabits per second, with second generation plans to be increased to a higher data transmission speed. It uses packets switching protocol based on a frequency hopping scheme, namely, frequency hopping spread spectrum (FHSS). Also, because of its omnidirectionality, authentication and encryption is also included, for security reasons, as part of the baseband protocol. That is, authentication relies on utilizing a secret key (i.e., password or PIN), thereby assuring security.
With the further refining of the standard as well as the emergence of new standards in the telecommunications fields including, although not limited thereto, the Bluetooth SIG standard, any previous or even the current Bluetooth specification (released on Nov. 29, 1999) does not provide for an architecture allowing wireless devices (wireless terminals or wireless transceiver devices) to communicate and coexist independently of the protocol version. In the earlier as well as in the present standard, there is no provision for any straight forward ways of making revisions to support plural (different) protocol versions including, for example, a previous (old) protocol version as well as a newly implemented, more advanced version, simultaneously. Although the receiver of a wireless transceiver unit, for example, correlates against the device access code (i.e., the receiver listens for its own DAC for the duration of the scan window) when in the page scan substate, and similarly correlates against the Inquiry Access Code (IAC) when in an inquiry scan mode, it is limited to linkups with only compatible protocol versions. That is, if a wireless device which is supported by an old protocol version is attempting to discover (i.e., linkup with) all wireless devices (e.g., mobile phones, etc.) located in a given range, it would not be able to locate devices having a revised or more advanced protocol version.
Conventionally, wireless devices belonging to one piconet network use one access code. For example, a Bluetooth receiver employs correlation which conforms to a preset protocol which defines the particular channel access code associated therewith. That is, each Bluetooth packet has a channel access code field in the packet header. Devices belonging to one ad hoc network use one access code while devices in other networks use other access codes. The access code is derived from the device identity code of the network master node. Accordingly, all the networks have unique access codes and thus can coexist in the same physical space without logically colliding. Some access codes have been reserved for the network management functions. However, due to the development of new or more advanced protocol versions, wireless devices are being manufactured which may not be able to be communicated with older version devices or devices having a different protocol version.
The present invention is directed to a communication system for providing one or more networks and including wireless devices which operate on certain radio frequencies. In accordance with such a scheme, at least one of those wireless devices in the network includes a transceiver having a receiver portion which simultaneously correlates an access code of an incoming data packet against the access code field associated with plural wireless protocol versions, supported by that wireless device, in a manner to permit a linkup between that wireless device and any of the other wireless devices, the other wireless devices including ones which support a linkup in accordance with only one of those wireless protocol versions. Such a simultaneous correlation is able to simultaneously distinguish between different access codes. According to the invention, the receiver portion of each wireless device that supports at least two wireless protocol versions includes as many correlators as are the number of wireless protocol versions that wireless device supports simultaneously. The different protocol versions involved may support devices which operate, as one example, on an ISM frequency band, although not limited thereto, where one such protocol version thereof may be limited to an earlier version (or standard) while the other may correspond to a more advanced protocol version. The ISM frequency band may be the 2.4 GHz ISM radio band for frequency hopping spread spectrum (FHSS) communication including conforming to the Bluetooth standard, although not limited thereto.
In accordance with one aspect, the receiver portion of each wireless device supporting plural wireless protocol versions features an RF modem which is coupled to an antenna port and which transmits the received signal to a demodulator where the signal is demodulated and is to be sampled as a packet data; at least two correlators which are simultaneously fed with a packet bit stream of the demodulated signal, these correlators which correspond in number to the number of wireless protocol versions supported by each such wireless device correlate (match) the access code of the packet bit stream to that one of the correlators programmed with a matching protocol; a sampler which samples and synchronizes the timing of the packet bit stream to the matched protocol; and in accordance with the outcome of the correlation, a sample bit stream is transmitted via a protocol matching parser to the appropriate buffer registers. The protocol matching parser may be in the form of a plurality of packet de-composers equal in number to the number of correlators such that each of the packet de-composers is programmably matched to a respective correlator on the basis of the protocol.
The lack of a protocol version field in the frame structure is circumvented through the addition of at least one more correlator, operating in parallel, in order to support at least two different protocol versions simultaneously. One such correlator may be programmed for an older access code or older inquiry access code while the additional correlator is programmed with the newer or revised access code or revised inquiry access code. That is, in accordance with a featured aspect of the present invention, the device listens to two or more different access code simultaneously, depending on the number of simultaneous correlations being effected. The access codes derived from the identifiers of the old and the revised protocol are programmed into the correlators. Both the correlators simultaneously receive the same data packet. On the basis of the matching effected by the simultaneous correlation, a selection is made as to whether the receiver is to handle the incoming bit stream according to the old or to the revised protocol.
The invention also features wireless devices having receivers that simultaneously correlate the codes of incoming data packets against that associated with plural wireless protocol versions, supported by each such wireless device, such that ad hoc linkups can be effected between that wireless device with other wireless devices which support only a single one of the protocol versions.
The invention also features a method which facilitates, in a communication system, an ad hoc connection between different ones of plural wireless transceiver devices which are supported by different protocol versions. In order to achieve such an ad hoc connection, the method calls for providing at least one such wireless transceiver device with a receiver portion to simultaneously correlate an incoming data packet against a plurality of protocol versions; synchronizing the timing of a sampling of the incoming data packet to produce a packet bit stream conforming to the protocol version matched by the simultaneous correlation; and on the basis of the matching effected by the correlation, transmitting the packet bit stream via a protocol matching parcer to either asynchronous data signal buffer registers or synchronous voice signal buffer registers or both, depending on the type of packet bit stream. If the packet bit stream consists of asynchronous connection-less (ACL) data packets, the parser (or packet de-composer) sends the packet bit stream to the asynchronous data signal buffer registers. If the packet bit stream consists of only synchronous connection-oriented (SCO) data packets then it is sent to the synchronous (voice) signal buffer registers. If the SCO packets are such that they carry both data and voice traffic, then they are appropriately parsed (separated) for storage in the corresponding ones of the registers.
In accordance with the present invention, total isolation of the protocol versions is maintained while allowing seamless coexistence and cooperation between different devices in the same network which may support different protocol versions. In accordance with the present invention, limitations are not placed on the protocol modifications due to the total isolation of the different protocol versions. For example, consider a revised master device in an ad hoc point-to-multipoint linkup. The master device (master node) controls the operation of all the slaves in that network. The revised slaves (which support plural wireless protocol versions through having at least two programmable correlators) respond to both the revised access code (RAC) and the access code of the original protocol version (OAC). Other slaves in that network, however, which are compliant only with regard to the old protocol version respond only to the access code of the original protocol version (OAC). Transmission which is under the RAC appears to the devices which are compliant only with the old protocol version as interference from some other network and, therefore, is ignored. During the normal operation, there is thus no risk of mixing the old and revised protocol version. Those devices which are compliant in accordance with the revised protocol version, according to the present invention, can support both protocol versions simultaneously.
The above set forth and other featured aspects of the invention are made more apparent and are further described in the ensuing detailed description of example embodiments and the claims when read in connection with the accompanying drawings, all forming part of the disclosure of this invention. While the foregoing and following illustrated disclosure focuses on disclosing example embodiments of the invention, it should be clearly understood that the same is by way of illustration and example only and the invention is not limited thereto. The spirit and scope of the present invention are limited only by the terms of the appended claims.
The following represents brief descriptions of the drawings wherein: